Some effects of epidermal growth factor at three stages of pregnancy in Merino ewes

1991 ◽  
Vol 42 (8) ◽  
pp. 1301
Author(s):  
IG Hazelton ◽  
BA Panaretto ◽  
PR Stockwell ◽  
JT Marshall ◽  
CD Nancarrow
Keyword(s):  
Body Weight ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Gestational Age ◽  
Untreated Control ◽  
Induced Abortion ◽  
Mechanisms Of Action ◽  
Plasma Progesterone ◽  
Epidermal Growth ◽  
Three Stages

Pregnant Merino ewes were treated with 90 8g murine epidermal growth factor (EGF) per kg body weight at either 25 (n = 80), 50 (n= 40) or 75 (n =40) days of gestation. Untreated control ewes were included at each gestational age (n=20, 12 and 12 respectively). Fifteen and twenty per cent of the ewes treated with EGF at days 25 and 50 respectively failed to lamb, significantly more (P < 0.01 ) than in ewes treated at day 75, where only one ewe failed to lamb, and in control ewes which all lambed. These differences were not reflected in significant differences between the overall percentage of lambs born in each group, as the incidence of abortion in single-bearing ewes was higher than in ewes carrying multiple fetuses. All lambs born alive to EGF-treated ewes appeared normal. Plasma progesterone concentrations measured before treatment and at 8, 24 and 48 h after EGF injection fell significantly in treated ewes relative to controls (P<0.01 at day 25; P<0.05 at days 50 and 75) and concentrations were lowest at 8 and 24 h after injection in those ewes which aborted. Following EGF treatment at days 25 and 50 of gestation, abortion occurred in all ewes with very low plasma progesterone concentrations 8 to 48 h after EGF injection, probably as a result of EGF-induced luteolysis. In other ewes plasma progesterone concentrations returned to pretreatment values by 48 h, indicating incomplete luteolysis. The delayed abortion observed in some of these ewes further suggests that other mechanisms of action are involved in EGF-induced abortion.

Effect of epidermal growth factor on glucosamine-6-phosphate synthetase activity in the colon of neonatal mice

1985 ◽  
Vol 105 (2) ◽  
pp. 197-200 ◽  
Author(s):  
M. Hiramatsu ◽  
M. Kashimata ◽  
N. Minami ◽  
N. Minami ◽  
M. Kumegawa
Keyword(s):  
Body Weight ◽  
Enzyme Activity ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Colonic Mucosa ◽  
Single Injection ◽  
Synthetase Activity ◽  
Apparent Effect ◽  
Neonatal Mice ◽  
Epidermal Growth

ABSTRACT Epidermal growth factor (EGF), administered subcutaneously to neonatal mice at daily doses of 1, 2 and 4 μg/g body weight for 3 days, significantly increased glucosamine-6-phosphate synthetase activity in the colon. A single injection of EGF at doses of 2 and 4 μg/g body weight also significantly increased enzyme activity. When administered to mature mice, EGF (4 μg/g body weight for 3 days) had no apparent effect on the enzyme activity. From these results, we suggest that EGF acts as a trophic factor for the maturation of the colonic mucosa of neonatal mice. J. Endocr. (1985) 105, 197–200

Effect of mouse epidermal growth factor on fertility in rams

1990 ◽  
Vol 41 (6) ◽  
pp. 1147 ◽  
Author(s):  
BW Brown ◽  
PE Mattner ◽  
BA Panaretto ◽  
GH Brown ◽  
BD Gream ◽  
...  
Keyword(s):  
Body Weight ◽  
Survival Rate ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Post Treatment ◽  
Sperm Production ◽  
Teratogenic Effects ◽  
Progressive Motility ◽  
Epidermal Growth ◽  
Daily Sperm Production

Seminal characteristics and flock fertility were studied in Merino rams treated with mouse epidermal growth factor (EGF). Intravenous infusions of 105 8g EGF/kg body weight over 24 h in five rams had no statistically significant effect on daily sperm production measured from 6-10 weeks after dosing or on the percentages of spermatozoa that were unstained (nigrosinleosin stain) or morphologically normal. At 7-8 weeks post treatment, the percentage of spermatozoa exhibiting progressive motility was significantly reduced (P<0.05). By 9-10 weeks after treatment, the seminal characteristics were normal in all rams. In 1987, eight rams and in 1988, six ofthe same rams, were joined with ewes for 6 weeks (at a rate of 2%) 12 weeks after s.c. injection of 150 8g/kg body weight. Compared with the performance of control rams, EGF had no significant effect on ram fertility, nor did it produce any teratogenic effects in their progeny or effect their survival rate.

scholarly journals Extracellular Na+ and initiation of DNA synthesis: role of intracellular pH and K+.

1984 ◽  
Vol 98 (3) ◽  
pp. 1082-1089 ◽  
Author(s):  
C P Burns ◽  
E Rozengurt
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Dna Synthesis ◽  
Cellular Proliferation ◽  
Weak Acid ◽  
Mechanisms Of Action ◽  
Epidermal Growth ◽  
Reversible Time ◽  
Stimulation Of

Initiation of DNA synthesis in confluent quiescent 3T3 cell cultures stimulated by epidermal growth factor (EGF), vasopressin, and insulin was abolished by removing extracellular Na+. The inhibition was reversible, time- and Na+-concentration-dependent, and not due to an effect on binding or internalization of 125I-EGF. Stimulation by combinations of other growth factors with different mechanisms of action was also affected by decreasing extracellular Na+, but with different half-maximal Na+ concentrations. When choline was used as an osmotic substitute for Na+, the decrease in DNA synthesis was correlated with the decrease in intracellular K+. In contrast, when sucrose was used there was stimulation of the Na+-K+ pump and maintenance of intracellular K+ that resulted in a somewhat higher rate of DNA synthesis at lowered extracellular Na+ compared to choline. Mitogenesis induced by epidermal growth factor, vasopressin, and insulin led to cytoplasmic alkalinization as determined by an increase in uptake of the weak acid 5,5-dimethyloxazolidine-2,4-dione. Experimental decrease in extracellular Na+ blocked this cellular alkalinization. Therefore, under some conditions the supply of extracellular Na+ may limit cellular proliferation because of a reduction in the provision of Na+ to the Na+/H+ antiport and resultant failure of alkalinization. We conclude that Na+ flux and its effect on intracellular K and pH has a major role in the complex system that regulates proliferation.

Effects of depilatory doses of epidermal growth factor on subsequent fertility, pregnancy rate and lambing performance in Merino ewes

1994 ◽  
Vol 45 (2) ◽  
pp. 333 ◽  
Author(s):  
BW Brown ◽  
PR Stockwell ◽  
BA Panaretto
Keyword(s):  
Body Weight ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Pregnancy Rate ◽  
Genetically Engineered ◽  
Dose Rates ◽  
Expected Time ◽  
Subsequent Fertility ◽  
Retention System ◽  
Epidermal Growth

In the present study on Merino ewes, murine epidermal growth factor (mEGF) and genetically engineered methionine epidermal growth factor (met-EGF), given at depilatory dose rates (120 8g mEGF/kg body weight (n = 82) and 250 8g met-EGF/kg body weight (n = 100) respectively), were assessed for effects on fertility, pregnancy rate and lambing performance. Following EGF injection, the ewes were fitted with a net retention system to hold the fleece on the animals for 5 weeks, at the end of which time the wool was harvested from the EGF-treated ewes by hand and was shorn conventionally from non EGF-treated controls (n = 100). All ewes were then joined to raddled-harnessed entire rams (2%) for 6 weeks. The dates of raddle markings recorded during the teaser period and during joining to entire rams revealed that the majority (97%) of control ewes were in oestrus at expected times during the joining period, whilst significantly (P < 0.001) fewer ewes in the mEGF (75%) and the met-EGF (65%) treated groups exhibited oestrus at the expected time. The majority of the ewes that were delayed in onset of oestrus were at the mid to late luteal stages of the oestrous cycle at the time of EGF treatment. There was no material difference between the three groups in the number of ewes returning to service during the joining period, or in the number of empty ewes. The three groups were also similar in the proportions of ewes bearing single or twin lambs, in the overall lambing percentage (controls 108010, mEGF 109%, et-EGF 107%) and survival of lambs to weaning. No abnormalities were found in any of the lambs. It appears that an interval of 5 weeks between dosing and joining is sufficient time for EGF-treated ewes to resume normal cyclicity and fertility.

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